Steam engine



Nov. 29, 1927. 1,650,642 H. e. MUELLER STEAM ENGINE Filed April 8. 19212 Sheets-Sheet 1 Kit ?atented Nov. 29, 1927.

narrate strains i ttt ttiiz HERMAN G. MUELLER, G16 EH13,PENNSYLVANIA,'ASSIGETOR TO SKINNER ENGINE COMPANY, or Eran,:enurvsrrvaure,

A COBPORATTGN 9F YENNSYLVANIA.

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Application filed A rii s,

In operating steam engines difliculty is experienced in maintaining themost efi'ective and desirable compression where there ls-a variableback-pressure on the exhaust; WV1th the present invention the volume ofsteam compressed is varied so as to control the compression. It is alsodesirable to vary the compression in relation to the supply pressure.The supply pressure ordinarlly does not vary greatly so that a changewith relation to it is not as important, perhaps, as the variation dueto changes in thegback pressure yet it affords an advantage and thepresent invention accomplishes this result.

panying drawings as follojwsz- Fig. 1 shows a side elevation of an engine, partly in section. v c Fig. 2 a horizontal section of the engine.

Fig. 3 a section "on the line 33 in Fig. 1; 1 marks the cylinder, 2 thepiston operating in the cylinder, 3 the steam supply pipe supplyingsteam through the ordinarypoppet valves 4, the valves receiving theirmotion from a lay shaft 5 through bellcr'anks' 5 operating on theiva-lvestems 5 An ek haust system comprises an exhaust port 6 which is arrangedinthe center eruietyun; ider, the engine shown being of the un'aflowtype and auxiliary exhausts which arepreferably supplied at 7,;thesebeing controlled by the usual valvesat'i It will be understood that thevalves at 7 close in the usual manner during the power stroke but areopen during the exhaust stroke so the compres sion follows the cut-citafforded by the port 7. It will be understood, however that the exhaustsystem may comprise only the ports 6 in the usual manner of centralexhaust unaflow engines if desired. In order to control he compressionwith a varying exhaust I prefer to provideanvary- .ing clearance whichvaries automatically as" the compression varies so as to control it" andto have the supply pressure a factor n this controlso that variations inthe supplypressure will alsojhave aresponse inthe variations inclearance. Clearance cylinders 8 are connected by ports 9 with the endsof the cylinder 1. Pistons 10 are arranged in the cylinders 8. Stemsllextend from the pistons 10 through the glands 12, these stems beingpreferably provided with. the gradua tions 13 to indicate the positionof the piston. Pipes let lead from the cylinders 8 to a come Theinvention is illustrated in the accom- 1921. Serial 1%. 459510.

mon chamber 15. The chamber 15is con nected by a pipe 16 with each oneofthe pas sages 17 connected with the supply so that the chamber 15 isunder supply steam pressure at all times. The chamber 15 is preftendingthrough the pipes let into the ends of the cylinders 8. Valves 18are arranged in the pipes 14, these vavles being of the plug valve typehaving the plugs 19 with ways 20. Stems 21 extend from the plugs 19.Rock arms 22 are arranged on the stems 21 connected by links 23 with therock arms 24: on the lay shaft. In the operation of the present devicethe valve 18 at the same end of the cylinder as the piston is openedthrough the action of the lay shaft and the connecting link 23011 thereturn stroke of the piston just prior to the moment the piston reachesits extreme erably partially filled with oil, this oil exposition. Thevalves 18 are closed approximately' at the point of cut-off, Thepressure which is delivered on the pistons 10 and the chamber 8 from thecylinder side, that is, the eliective'pressure, is; the mean pressure ofthe cylinder during thetime the pressures are opposed on thepistons 10.I It will be noted that the pistons will take any position necessary tomaintain the proper clearance space. During the periodthat the pist0n10is thussubjected to the cylinder pressure the opposite face of thepiston" is subjected to supply pressure by reason of the opening of thevalve 18. It win he noted that the piston is of greater area on itssurface subjected to the cylinder pressure than on the surface subjectedto the supply steam pressure 1 through the pipe lhy reason of the areaof the stem 13. This difference represents the difference in thecylinderpressure with a normal back-pressure and supply pressure. Ifthere is an abnormal back-pressure this will; result in an abnormalcompression, which being communicated to the cylinder 8 will move thepiston 10 outwardly thus in creasing theportion er the cylinder 8 incommunication with the ends ot'thecylinder and forming apart of theclearance space. This outward change will be in the nature of a" seriesof outward movements until equilibrium is established. On the other handifthe back-pressure shouldbe reduced] so thatthe added clearance is sogreat as to reduce the compression below what it should be this lowercompression Wlli be felt in the:

cylinders 8 and the preponderance of supply pressure will move thepiston 10 inwardly reducing the clearance space. It will be noted thatas the clearance is varied by the variation of the location of thepiston in the cylinder 8 the volume of steam compressed is varied andthat the initial compression clearance space is also varied and thatthis variation is in proportion to the variations in back pressure.Again if the supply pressure should be increased so as to make a highercompression desirable this preponderance of supply pressure over thecompression of the moment will move the piscylinder; and meanscontrolling said clearance varyingpistons at the initial compression forvarying their position as the exhaust back-pressure varies.

2. In a steam engine, the combination of a power cylinder having anexhaust system cutting off the exhaust for compression; a power pistonin the cylinder; clearance chambers connected with the cylinder at itsends; clearance varying pistons in the chambers varying the capacity ofthe chambers lII'COIlIlBCtlOD with the power cylinder; and

means controlling said clearance varying pistons at the initialcompression for varying their position as the supply steam pressurevaries.

3. Ina steam engine, the combination of a power cylinder having anexhaust system cutting off the exhaust for compression; a power pistonin the cylinder; clearance chambers connected with the cylinder at itsends; clearance varying pistons in the chambers varying the capacity ofthe chambers in connection with the power cylinder; and meanscontrolling said clearance varying pistons at the initial compressionfor varying their position as the supply steam pressure and exhaust backpressure varies.

.4. In a steam engine, the combination of a power cylinder having anexhaust system cutting off the exhaust for compression; a power pistonin the cylinder; clearance chambers connected with the cylinder at itsends; clearance varying pistons in the chambers varying the capacity ofthe chambers in connection with the power cylinder, said pistons havingdifferential faces, the larger face being subjected to the )owercylinder pressure and the smaller ace to supply steam pressure; a valvegear for the engine; and means acting with said valve gear con trollingthe action of the supply steam on the clearance varying pistons.

5. In a steam engine, the combination of a power cylinder having anexhaust system cutting off the exhaust for compression; :1. power pistonin the cylinder; clearance chambers connected with the ends of thecylinder; clearance varying pistons inthe clearance chambers; liquidconnections leading from said clearance chamber; liquid in saidconnections; means for subjecting the liquid to supply steam pressure;valves in the liquid connection; a valve gear for the engine; and meansacting with the valve gear controlling said valves.

6. In a steam engine, the combination of a power cylinder having anexhaust system cutting off the exhaust for compression; a power pistonin the cylinder; clearance chambers connected with the ends of thecylinder; clearance varyingpistons in the clearance chambers; liquidconnections leading from said clearance chamber; liquid in saidconnections; means for subjecting the liquid to supply steam pressure;valves in the liquid connections; a valve gear for the engine; meansacting with the valve gear controlling said valves; and stems extendingfrom said clearance varying pistons to without the chamber and reducingthe effective area of the pistons.

7. In a steam engine, the combination of a power cylinder having anexhaust system cutting off the exhaust for compression; :1

'power piston in the cylinder; clearance chambers connected with theends of the cylinder; clearance varying pistons in the clearancechambers; liquid connections leading from said clearance chamber; liquidin said connections; means for subjecting the liquid to supply steampressure; valves in the liquid connections; a valve gear for the engine;means acting with the valve gear controlling said valves; and stemsextending from said clearance varying pistons to without the chamber andreducing the etlective area of the pistons, said stems havinggraduations indicating the position of the clearance varying pistons.

In testimony whereof I have hereunto set my hand.

HERMAN G. MUELLER.

